\(B=\frac{\left(80+192+4480\right)}{\left(270+648+15120\right)}\)

     \(=\frac{4752}{16038}\)

       \(=\frac{8}{27}\)

vì sao??

bạn tính như bt là ra mà ???

\(\frac{2\cdot4\cdot10+4\cdot6\cdot8+14\cdot16\cdot20}{3\cdot6\cdot15+6\cdot9\cdot12+21\cdot24\cdot30}\)

\(=\frac{8\cdot1\cdot2\cdot5+8\cdot2\cdot3\cdot4+8\cdot7\cdot8\cdot10}{27\cdot1\cdot2\cdot5+27\cdot2\cdot3\cdot4+27\cdot7\cdot8\cdot10}\)

\(=\frac{8\cdot(1\cdot2\cdot5+2\cdot3\cdot4+7\cdot8\cdot10)}{27\cdot(1\cdot2\cdot5+2\cdot3\cdot4+7\cdot8\cdot10)}=\frac{8}{27}\)

\(\frac{2.4.10+4.6.8+14.16.20}{3.6.15+6.9.12+21.24.30}\)

\(=\frac{2\left(1+2+5\right)+2\left(2+3+4\right)+2\left(7+8+10\right)}{3\left(1+2+5\right)+3\left(2+3+4\right)+3\left(7+8+10\right)}\)

\(=\frac{2\left(1+2+5+2+3+4+7+8+10\right)}{3\left(1+2+5+2+3+4+7+8+10\right)}\)

\(=\frac{2}{3}\)

Đáp án bằng \(\frac{8}{27}\)mà Nguyễn Châu Tuấn Kiệt,sao ai cũng k sai mk hết nhỉ??

Tử số bạn lấy thừa số chung là 2.4.10 còn ở mẫu bạn lấy thừa số chung là 3.6.15 là ok

\(B=\frac{2.4.10+4.6.8+14.16.20}{3.6.15+6.9.12+21.24.30}\)

\(B=\frac{2.4.2.5+4.2.3.2.4+7.2.4.4.2.10}{3.6.3.5+6.3.3.12+3.7.4.6.3.10}\)

\(B=\frac{2.2.4.\left(5+4.3+7.4.10\right)}{3.3.6\left(5+12+7.4.10\right)}\)

\(B=\frac{2.2.4.\left(5+12+7.4.10\right)}{3.3.6\left(5+12+7.4.10\right)}\)

\(B=\frac{2.2.4}{3.3.6}=\frac{2.2.2}{3.3.3}=\frac{8}{27}\)

Bài này không khó lắm bn hãy nhìn cách làm của mk nhé!

B=\(\dfrac{2.4.10+4.6.8+14.16.18}{3.6.15+6.9.12+21.24.30}\)= \(\dfrac{2\left(1.2.5+2.3.4+7.8.10\right)}{3\left(1.2.5+2.3.4+7.8.10\right)}\)

= \(\dfrac{2}{3}\)

Vậy B=\(\dfrac{2}{3}\)

Nếu bn nghĩ là đúng hãy tick cho mk nha!

Chúc bn học tốt!!!

B= 2.4.10+4.6.8+14.16.20/3.6.15+6.9.12+21.24.30

B=2.[1.2.5 +2.3.4 +7.8.10]/3.[1 .2.5+2.3.4+7.8.10]

B=2/3

B = \(\dfrac{2.4.10+4.6.8+14.16.20}{3.6.15+6.9.12+21.24.30}\)
B = \(\dfrac{2^3.\left(1.2.5+2.3.4+7.8.10\right)}{3^3.\left(1.2.5+2.3.4+7.8.10\right)}\)
B = \(\dfrac{2^3}{3^3}\)
B = \(\dfrac{8}{27}\)

\(=\dfrac{8\cdot10+8\cdot24+8\cdot28\cdot20}{18\cdot15+18\cdot36+18\cdot840}=\dfrac{8\left(10+24+560\right)}{18\left(15+36+840\right)}=\dfrac{4}{9}\cdot\dfrac{2}{3}=\dfrac{8}{27}\)

\(N=\dfrac{2^{19}\cdot3^9-3\cdot3^8\cdot5\cdot2^{18}}{3^9\cdot2^9\cdot2^{10}-2^{20}\cdot3^{10}}\)

\(=\dfrac{2^{18}\cdot3^9\cdot\left(2-5\right)}{3^9\cdot2^{19}\left(1-2\cdot3\right)}=\dfrac{1}{2}\cdot\dfrac{-3}{-5}=\dfrac{3}{10}\)

\(P=\dfrac{8\cdot10+8\cdot24+8\cdot560}{6\cdot45+6\cdot108+6\cdot120\cdot21}=\dfrac{8\left(10+24+560\right)}{6\left(45+108+120\cdot21\right)}=\dfrac{4}{3}\cdot\dfrac{2}{9}=\dfrac{8}{27}\)